The present invention relates to a new and distinct cultivar of peach rootstock (Prunus persica) that has been denominated as ‘HBOK 50’ and more particularly to a peach rootstock that is graft compatible with peach and nectarine scion cultivars, and confers moderate vigor control on compound trees, produce fewer root suckers than ‘Nemaguard’, and is resistant to the rootknot nematode Meloidogyne incognita (race 1) isolate ‘Beltran’.
It is recognized that vigor control of compound trees on a standard rootstock, such as ‘Nemaguard’, is difficult to achieve and to do so requires extensive pruning both in mid summer and the dormant season. It is also recognized that root suckers produced on standard rootstock are required to be removed manually, resulting in cost to the grower. The ‘HBOK 50’ peach rootstock has modest vigor control that produces smaller trees, which requires less pruning, and much fewer root suckers than ‘Nemaguard’, which results in cost savings for the grower.
The peach rootstock of the present invention was created at Davis, Calif. In 1990 hybrid ‘P248-139’ was created by crossing ‘Harrow Blood’ (HB) with ‘Okinawa’ (OK) at Fresno Calif. ‘Harrow Blood’ was used as the female parent and ‘Okinawa’ was used as the male parent in the cross. Seeds resulting from the open pollination of a single F1 plant from hybrid ‘P248-139’ were used to generate an experimental population (referred to as ‘OP-F2 population’) in February of 1994. Fifty seven ‘OP-F2’ seedlings were budded with ‘O'Henry’ (referred to as ‘O'Henry population’), and concurrently each of these seedlings was budded onto ‘Nemared’ rootstock (referred to as ‘OP-F2 population’). There were no obvious defects in the bud unions indicating compatibility of scions and rootstocks at this stage. Compound trees of ‘O'Henry’ scion budded onto each seedling of the ‘OP-F2’ segregating population as a rootstock were evaluated for trunk cross-sectional area (TCA), tree height, crop yield, cropping efficiency, fruit weight, and number of suckers. Eight seedlings were selected for further study of rootstock potential under semi-commercial conditions at Parlier, Calif. The primary criterion used for choosing seedlings having potential for size control as a rootstock was TCA. Wood from mother trees was propagated asexually (rooted), budded with ‘O'Henry’ peach scion and planted in a replicated field trial at Parlier, Calif. in 1999. ‘HBOK’ 50 was identified as a result of that trial, and was subsequently selected for further horticultural evaluation.
The new ‘HBOK 50’ peach rootstock of the present invention has been asexually reproduced by leaf cuttings at Davis, Calif. The distinctive characteristics of the new peach rootstock have been found to be stable and are transmitted to the new rootstocks when asexually propagated.